Genetics Notes Final Exam Chapter 23

Genetics Notes Final Exam Chapter 23 - Extranuclear DNA &...

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Chapter 20 Notes Extranuclear DNA 1. DNA outside of nucleus a. Mitochondrial DNA [mtDNA] b. Chloroplast DNA [cpDNA] 2. Exhibits cytoplasmic inheritance 3. Endosymbiotic Theory a. Origin of membrane-bound organelles i. Mitochondria ii. Chloroplasts b. Originated from free-living bacteria and were engulfed by heterotrophic cell. c. Proposes that mitochondria and chloroplasts in eukaryotic cells arose from eubacteria. 4. Organelle DNA a. Multiple copies/cell b. Expresses cytoplasmic inheritance c. Homoplasmy—one genetic type in cell d. Heteroplasmy—two or more genetic variants in cell e. Replicative segregation 5. Mitochondrial DNA [mtDNA] a. Size and structure i. One double-stranded DNA molecule per genome ii. No histone proteins iii. Usually circular iv. Small but variable in size 1. Vertebrate mtDNA—15kb 2. Yeast mtDNA-75kb
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3. Plant mtDNA—250-2400kb 4. See Table 20.1—don’t need to memorize though b. Organization—ancestral and derived genomes i. Ancestral mt genomes 1. In plants and protists 2. Numerous genes 3. Bacterial-like genomes 4. Complete set of tRNAs 5. Few introns 6. Little noncoding DNA between genes 7. Only universal codons present ii. Derived genomes 1. In animals and fungi 2. Smaller in size and fewer genes 3. Nonbacterial ribosomes 4. Incomplete sets of tRNAs 5. Introns present 6. Noncoding DNA between genes 7. Nonuniversal codons present iii. Human mtDNA—16.5 kb 1. 2 rRNA genes 2. 22 tRNA genes 3. 13 protein genes 4. Economy of sequence 5. Only 2 origins of replication 6. Little noncoding DNA between genes
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7. No introns 8. Only 1 promoter per nucleotide strand 9. Some stop codons missing iv. Yeast mtDNA—75kb 1. 2 rRNA genes 2. 25 tRNA genes 3. 16 protein genes 4. Numerous origins of replication 5. Vast noncoding DNA between genes 6. Introns present c. Replication of mtDNA i. Occurs throughout cell cycle ii. Special DNA polymerase [DNA pol gamma] 6. Chloroplast DNA a. One double-stranded DNA molecule b. Usually circular c. No histone proteins d. Size i. 120-200,000bp e. Introns present f. Much noncoding DNA between genes. g.
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This note was uploaded on 05/09/2008 for the course BIO 2306 taught by Professor Durhkopf during the Fall '08 term at Baylor.

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Genetics Notes Final Exam Chapter 23 - Extranuclear DNA &...

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